A bracelet corresponding to the general definition which has just been given is described in the Swiss patent document CH-A-566 744. This bracelet includes a longitudinally flexible core of plastic material the lower face of which includes a succession of grooves separated from one another by projections. It also includes a series of covering elements each comprising a lower part and an upper decorative part which may be metallic, for instance stainless steel or gilded metal. The lower part includes a lower wall applied against the surface of one of the projections of the core and two substantially parallel lateral walls applied against the lateral walls of the same projection. The upper part includes an upper wall applied against the surface of the core and two end walls descending along the longitudinal edges of the band each ending with a central foot which is bent into a slot borne by the lower part. The covering elements are thus solidly positioned relative to one another by means of the grooves, thereby avoiding unequal gaps between the covering elements of the assembled bracelet. It can be likewise mentioned that the core of plastic material is hidden from sight by the fact that one of the sides of the upper part includes teeth which project into cavities formed in the contiguous side of the neighbouring upper part.
This construction exhibits several difficulties. It may be mentioned initially that the grooves provided in the core of plastic material comprise numerous weak points and that cracks may begin therein due to fatigue stress which may in time bring about breaking of the bracelet. In order to avoid this, one could increase the existing thickness between the top of the core and the bottom of the groove but this to the detriment of the overall thickness of the bracelet.
It may likewise be mentioned that the described bracelet requires special tooling in order to effect assembly of the covering elements. Thus, the upper part must be bent in order to hook into the lower part. While this assembly may readily be undertaken in the factory on automatic machinery, the question then arises of fixing the length of the bracelet which is generally done by the watch maker repairman on request of the customer. Should the bracelet require shortening, it will necessitate initially removing from the core the end covering element by spreading out the central feet of its upper part which will not be accomplished without trouble and without deforming said part to such an extent that it will be rendered useless and it will thereafter be necessary to fit a new part. Next, it will be necessary to remove from the core at least one complete covering element, to cut the core by the length of one projection and to reassemble it on the lower part of the end covering element by bending over onto it a new upper part. All these operations are delicate and above all risk not being carried out with the desired care in view of the lack of a suitable tooling.
Finally, it will be noted that the teeth with which the upper parts are provided comprise undesirable roughnesses susceptible to hook onto various objects as for instance the wrist portions of shirt sleeves which may consequently be damaged.